Interpretive Summary: Doubled haploid (DH) techniques, an approach to accelerate homozygosity, are a useful tool for conventional and molecular plant breeding, and genetic studies. The Oregon Wolfe Barley (OWB) mapping population is a resource for genetics research and instruction in barley (Hordeum vulgare L.). This population comprised of 82 DH lines was developed by interspecific crossing of Hordeum bulbosum (H.b.) as a male parent to the F1 of the cross between the dominant and recessive morphological marker spring barley genetic stocks developed by R. Wolfe in 1972 as a female parent. After spontaneous elimination of H.b. chromosomes, the DH population was generated by embryo rescue, plant regeneration followed by artificial chromosome doubling. Therefore, the DH population developed by H.b. method samples female gametes. In this study, 93 new DH lines from the same cross between Wolfe’s dominant and recessive morphological marker stocks were produced using anther culture (A.C.) method, which samples male gametes. The goal of this project was to increase the size of the OWB mapping population in order to improve it as a resource for genetic mapping and quantitative trait association. We compared genetic maps based on A.C. and H.b.-derived subpopulations genotyped with the same 1,328 single nucleotide polymorphism (SNP) markers using the same genotyping assays. This allowed for direct comparisons of segregation distortion and genetic distance between DNA markers with the each of the two genetic maps, and empirical assessment of improvements in detection of quantitative traits afforded by doubling the size of the mapping population. The results showed that the genetic maps between two subpopulations revealed minor differences in terms of estimated recombination rates. No differences were found in DNA marker ordering on chromosomes. There was greater segregation distortion in the A.C.-derived subpopulation than in the H.b.-derived subpopulation, but in the region showing the greatest distortion, the cause was more likely the genetic variation at the gene controlling plant height (ZEO1) rather than to DH production method. The effects of segregation distortion had greater impacts on estimates of quantitative trait effect than population size for reproductive fitness traits assayed under greenhouse conditions. The OWB population and data are community resources. Seed is available from three distribution centers located in North America, Europe, and Asia. Details on ordering seed sets, as well as complete genotype and phenotype data files, are available at (http://wheat.pw.usda.gov/ggpages/maps/OWB/).

Technical Abstract:
The Oregon Wolfe Barley mapping population is a resource for genetics research and instruction. Prior reports are based on a population of doubled haploid (DH) lines developed by the Hordeum bulbosum (H.b.) method, which samples female gametes. We developed new DH lines from the same cross using anther culture (A.C.), which samples male gametes. Linkage maps were generated in each of the two subpopulations using the same 1,328 single nucleotide polymorphism (SNP) markers. The linkage maps based on DH lines derived from the products of megasporogeneis and microsporogenesis revealed minor differences in terms of estimated recombination rates. There were no differences in locus ordering. There was greater segregation distortion in the A.C.-derived subpopulation than in the H.b.-derived subpopulation, but in the region showing the greatest distortion, the cause was more likely allelic variation at the ZEO1 plant height locus rather than to DH production method. The effects of segregation distortion and pleiotropy had greater impacts on estimates of QTL effect than population size for reproductive fitness traits assayed under greenhouse conditions. The OWB population and data are community resources. Seed is available from three distribution centers located in North America, Europe, and Asia. Details on ordering seed sets, as well as complete genotype and phenotype data files, are available at (http://wheat.pw.usda.gov/ggpages/maps/OWB/).